Thread-trimming device for sewing machines



J. Knzwlcz THREAD TRiMMING DEVICE FOR SEWING MACHINES Dec. 8, 1925} Filed June 5, 1922 4 Sheets-Sheet l .R mh Nb QM. m. I], \l) N. B. 3 w I I I. w m y mm \nvenToT. dohn Kiewicg.

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Dec. 8, 1925 1,565,160 J. KIEWICZ THREAD TRIMMING DEVICE FOR SEWING MACHINES Filed June 5, 1922 4 Sheets-Sheet 3 John Kiewicg b iuw wxkm Afiys.

J. KIEWICZ THREAD TRIMMING DEVICE FOR SEWING MACHINES Dec. 8, 1925- 1.565.160

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23 dohn Kiewic Patented Dec. 8, 19.25.,

UNETELU @FFlQEs JOHN IIIEVTICZ, O13 BOISTON, ELESSACI-IUSETTS, ASSIGNQR TO REECE BUTTON HOLE MACHINE COMPANY, OE BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

THREAD-TEIMMING DEVICE FOR SEWING MACI-IZNES.

Application filed June 5,

To all whom it 122 (13 concern Be it known that 1. JOHN Kinwioz, a citizen of the United States, and resident of Bostom county of Suffolk, State of Massa chusetts, have invented an In'iprovement in 'lh1eadlrimming Devices for Sewing Machines, of which the following description, in connection with the accompanying drawing. is a specification, like characters on the drawing representing like parts.

This invention relates to thread-trimming devices for sewing machines of that type which are constructed to sew a short seam and then automatically come to rest. (a buttonholc sewing machine being an exemplification of this type of sewing machine) and said invention relates particularly to that class which are constructed to grip the thread at the end of each sewing or eration and to maintain such hold on the thread until the next sewing operation has begun and to cut the thread between the holding means and the work both at the end of each sewing operation and after the next succeeding sewing operation has begun.

Buttonhole sewing machines are usually provided with work-holding means and with stitch-forming mechanism arranged to have a relative movement both during the sewing of the buttonhole and subsequently thereto, the relative movement after the sewing operation has been completed being for the purpose of bringing the parts relatively into buttonhole-cutting position. Such sewing machines also are provided with an operating mechanism, such for in stance as a main cam, for providing such relative movement between the stitch-forming mechanism and the work-holding means.

One of the objects of my present invention is to provide a tlucadtrimming mechanism of the class above described in which the thread cutter is actuated by means associated with the main cam while the threadholding device is actuated by the relative movement between the WOll-GllOltllllg means and the stitch-forniing mechanism.

in sewing machines herein illustrated the work-holding means stationary while the fiiltPll l flllTl'l i mechanism ismounted on a 1922. Serial No. 566,019.

travelling. frame,-and another object of my invention is to provide a sewing machlne ha ving the stitclrforming mechanism sup-- ported by a travelling frame with a thread trinnner which is actuated or controlled by means associated with the main cam.

In the construction herein descril ed the thread-trimming means and the thread-hold ing means are carried by the work-holding means which in turn are removable from the bed frame of the machine and another object of the invention is to provide a novel operating means for the thread-holding means and thread cutter which does not interfere at all with the removal of the work-holding means from the machine.

Other objects of the invention are to improve generally thread-triimning devices of this nature all as will be more fully hereinafter set forth.

In order to give an understanding of the invention I have illustrated in the drawings some selected embodiments thereof which will now be described after which the novel features will be pointed out in the appended claims.

Fig. l is a side view of a portion of a buttonhole sewing machine having my improvements applied thereto.

Fig. 2 is an under side view of the bed frame showing some of the operative connections for controlling the thread cutter.

Fig. 3 is a plan view of a portion of the bed frame showing my improved threadtrimming means thereon.

Figs. l and 5 are fragmentary views showing the thread-trimming means in different positions.

The sewing machine shown in the drawings is formed with a bed plate 1 on which is supported work-holding means comprising clamp plates 2 on which the work supported and the usual work clamps 3 pivotally supported on the clamp plates 2. The machine also comprises stitch-forming mechanism of the usual type, such as is shown in lllnited States Patent N 655,637 Aug. 7, 1900 and it is supported on a head l, said stitch-forming mechanism comprising an upper needle 5 that reciprocates vertically and penetrates the work 10, said needle controlling the upper thread, and an under 7 needle (not shown) for controlling the under thread, and which operates through the throat plate 100.

The machine is also illustrated as having a buttonhole. cutter 6 by which the buttonhole is out.

The stitch-forming mechanism and the work-holding means have a relative 1nove ment during the stitching on the buttonhole and also after the buttonhole has been completed, the latter relative movement carrying the parts relatively from stitching position to buttonhole cutting position.

' In the machine herein shown this relative nioven'ient is secured by a movement of the head t on the bed frame 1, said head produeing a. movement of the stitch torining mechanism relative to the work-holding means. This movement of the head l is de rived through the medium of a main ca m 7 which is located in a housing 8. 1111 as shown in the above-mentioned patents.

When the machine has been brought to rest at the end of a stitching operation the head 1 is in the full line position Fig. 1 so that the work is in huttonhole-cutting po sition and when the machine is started in, operation the buttonhole cutter 6 is operated to cut the buttonhole after which the head 1 is shifted to the right to bring the stitclrtorming mechanism into the dotted line position Fig. 1 or into stitching position. At this time the stitcl to1'1ning mechanism is set in operation and the head (01% tinues to move further to the right whilethe stitching is performed down one side of the buttonhole and then to the left while thestitching on the buttonhole is completed after which the stitch-forming mechanism comes to est Wi'tfl the needle raised and the headis givcna further movement into the position shown in full lines Fig. 1. A more complete description of these operations will be found in the ahove-mentioned patent.

The work-holding means carries a threadholding device adapted to grip the needle thread at the end of the sewing operation, and a cutter which is adapted to cut the thread both at the end of the sewing opera tion and at the beginning of the next sew ing operation. The thread holder or thread gripper is in the form of an arm 9 pivoted at 10 to the clamp plate 2 and having at its free end a hook portion 11. (lo-operating with this thread-gripping arm is a plate 12 which is secured to the arm 13 of one of the work clamps 3, said plate being situated directly beneath the hook 11 and in engagement therewith. The thread gripper 9 is acted onbv a spring let which tends to hold it in the position shown in Fig. 3, in which position. is located at one side of the line nseaiso of stitching. Just before the stitching' on the buttonhole 18 completed the arm 9 is swung over into the position shown 111 Fig.

et carrying the hook 11 to the opposite side of the line of stitching and when the huttonhole is tally completed and the stitch- :torming mechanism has stopped with the needle raised the portion or the needle thread 15 extending from the work to the needle will be behind the hoot: 1.1. '1 he arn 9 is then given a movement into the position shown in F 5. during which time it engages the needle thread 15 between the work and the needle and clan'ips said thread between said} hook and the plate 12.

The thread cutter is shown as a cutting blade o 'ierating between the tlu'ezul-holding means and the work and carried by a swing ing arm 17 pivoted to the clamp plate at 18. This cutter is actuated after the thread is engaged by the holding means therelw to cut the thread between the thread-holding means and the work.

In my presentinvention I have provided novel means tor actuating the thread cutter 16, which means is associated with the main cam 7.

The arm 17 is shown as acted upon by a spring 19 which normally holds the cutter in its inoperative position shown in Figs. i-l and l.

vlltx'tending vertieall through the bed plate 1. is a rock shaft 20 having an arm 21 fast thereto at its upper end and lying above the bed Frame. said arm being adapted to engage the cutter arm 17 and give, it its cutting movement, as shmvn in Fig. I. The arm 21 is acted. on by a spring which normally holds it against a stop The rock shaft 20 also has an arm 241: last there on beneath the bed frame 1. and this has a downwardly directed portion 25 which c operates with a controlling lever 26 pivo ed to the cam housing 8 as shown at 27. The main cam 7 has a hub 29 rigid therewith which is formed with a controlling cam Ill). the latter being adapted to engage an extension 31 formed on the lever 26. aid lever 26 is acted on by a spring which normally holds it in engagement with the cam 30.

The construction of the parts is such that normallv the cutter will be held in its retracted position by its spring 19 and the rock shaft 20 will be held in a position by the spring 22 in which the arm 21 is separated from the cutter arm 17. At the times that the thread is to he cut the lever 26 given a movement toward the left Fig. 2 thereby to engage the extension 25 of the arm 24 and rock the shaft 20 into the position shown in Fig. 5. thereby causing the arm 21 to engage the cutter arm 17 and give the cutter 16 its thread cutting movement, The cam 36 is arranged so that this thread cutting movement will occur at the end of each sewing operation and again after the beginning of the next sewing oporation. For this purpose the cam is formed with a concentric face having two notches 3Z3, 3=ltherein. hen the foot or portion 31 rests against the face 35 the lever 26 is held in its inoperative position shown in Fig. 2 thereby permitting the rock shaft 20 and cutter arm 17 to assume their inoperative positions. \Vhenever one of the notches comes opposite the foot 31 then the spring 82 will give the lever 26 a quick movement to the left Fig. 2, which will operate to rock the rock shaft, 20 into the position shown in Fig. 5, thereby giving the cutter 16 its cutting movement. As soon as the notch passes by the foot 81 then the parts are restored to their normal inoperative position. These notches 33 and 34 are positioned so as to give the cutter its twocutting moven'ient in proper timed relation with regard to the forming of the buttonhole.

The thread-gripping arm E) may be given its actuation by any suitable means and in Figs. 1 to 5 I have shown a construction wherein this movement is derived from the relative movement between the stitch-forming mechanism and the work-holding means. The arm 9 is extended beyond the pivot 10 as shown at 36, and said extension carries a sleeve 37 from which depends an arm 38 provided with a foot 39 adapted to engage a projection 40 carried by the head 4. The sleeve 37 is acted on. by a. spring 41 which normally holds it against a stop t2 but which allows it to swing a *ay from the stop, and the construction is such that the projection. l0 engages the foot 39 while the stitching is being done near the end of the buttonhole at which the stitching begins and ends. In the stitching of the buttonhole the head 4 moves to the right so as to carry the needle down one side of the buttonhole and then it moves to the left to *arry the stitching along the opposite side of the buttonhole. During the movement toward the right the projection 4-0 engages the foot and merely swings it to one side away from the stop and does not there fore, operate the arm 9. During the move ment of the frame in the opposite direction and while the second side of the buttonhole is being stitched the projection 40 again engages the opposite side of the foot 39 and at this time it acts through the foot and arm which is then resting against the stop 41-2, to move lever 9 into the position shown in Fig. l, thereby carrying the hook 11 across the line of stitching in front of the needle. hen the stitch-forming mechanism comes to rest the parts will be in substantially the position shown in Fig. 4 and during the further movement of the frame toward the left to carry the parts relatively into buttonhole cutting position the projection a0 is carried away from the foot 3 9, thus allowing the spring 14: to give the thread-gripping member a quick move.- ment into the position shown in 5, which will. operate to take the needle thread 15 and clamp it against the plate 12. lVith this construction the thread-holding device operates once only for each buttonhole while the thread cutter has two actuations.

The operation of the device thus far described may be briefly smnmarized as follows:

.rssuming that the buttonhole has been stitched down one side and is being stitched on the other side, then during the stitching on the latter side the thread gripping arm 9 is swung into the position shown in Fig.

4: and when the stitching on the buttonhole is completed said thread-holding member is -arried into the position shown in Fig. 5 thereby gripping the needle thread between the work-holding means and the needle. After the thread is thus gripped the thread cutter 1G is actuated through the connections above described to cut the thread between the holding means and the work. This leaves the end of the needle thread retained in the holding means and such holding means maintains its hold on the needle thread until after the stitching on the next buttonhole has started. After the first few stitches on the next buttonhole have been formed then the cutter is given a second actuation to cut the end of the needle thread close to the. work thus leaving a thread fragment in the holding means.

I have also illustrated herein a cutter for cutting the under thread beneath the work. This cutter comprises two cuttingelements and 56 carried by two blocks 57. 58 that are pivotally connected at 59. and that have arms 60 and 61 extending therefrom. These arms are connected by a spring 62 which tends to separate the cutting elements 56. Situated between the arms 60, ($1 is a cam member 63 carried by a vertical shaft 64 that is supported in the machine frame. This shaft 64 has an arm 65 rigid therewith, the end of which is adapted to engage the shoe 68 on the end of a lever 69 pivoted to the cam housing at 70. This lever is acted on by a spring 71 tending normally to hold it in its inoperative position. The hub 29 of the main cam. is provided with an arm 72 having a roll 73thereon arranged so that during the rotation of the cam the roll will engage the end 7 1 of the lever 69 and swing the end 68 of the latter toward the center of the machine thereby actuating the rock shaft 64 and turning the cam member 63 so as to separate the arms 60, 61. This results in bringing the cutting elements of), 56 together nd. giving them their thread-cutting movement. After the roll 73 passes off from the lever 69 the parts 7 will be restored to their normal position.

This cutter for the under thread is not claimed herein but is made the subject of another application Serial No. (386,626 filed January 16th, 1924.

I claim:

1. In a sewing machine, the combination with work-holding means and stitch-forming mechanism having arelative movement, of means operated by such relative movement to seize and hold the thread after the completion of the seam, and can'i-operated means to cut the thread between the thread,- holding means and the work both at the end of the seam and at the beginning of the seam.

2. In a sewing machine, the combination with work-holding means and stitch-forum ing mechanism having a relative movement, (if-means operated by such relative movement to seize and hold the thread after the completion of the seam. and cam-operated means ope 'ating independently of said relative movement to cut the thread between the threadholding means and the work.

3. In a sewing machine, the combination with work-holding means, stitclnformin e' mechanism and a main cam to give them a relative movement, of means operated by such relative movement to seize and hold the thread at the end of the seam, a thread cutter, and means associated with the main cam to operate the cutter independently of said relative movement to cut the thread between the thread-holding means and the work.

4. In asewing machine, the combination with work-holding means, stitch-forming mechanism and a main cam to give them a relative movement,- of means operated by such relative movement to seize and hold the thread at the end of the seam, a thread cutter, and means associated with the main cam to operate the cutter to cut the thread between the thread-holdina means and the work both at the end of the seam and at the beginning of the seam.

5. In a sewing, machine, the combination with work-holding means, stitch-forming mechanism, a cam for giving them a relative movement, said stitch-forming mechanism including a needle adapted to penetrate the work, of means operated by such relative movement to seize and hold the needle thread after the completion of the seam, a thread cutter to cut the needle thread, and means rotating; with said cam to actuate said cutter.

6. In a sewing machine, the combination with work-holding means, stitch-forming, mechanism, a cam for giving them a relative movement, said stitch-forming mechanism including aneedle adapted to penetrate the work, of means operated by such relative movement to seize and hold the needle thread after the completion of the seam, and means associated with said cam to cut the thread both at the end of the seam and at the beginning of the next seam.

T. In a sewing machine, the combination with work-holding means, stitch-forn'ling mechanism and a cam for giving them a relative movement, of means operated by the relative movement to seize and hold the thread at the completion of the seam, a thread cutter, a cutter controlling cam rigid with the main cam, and connections between said, cam and cutter by which the cutter is caused to cut the thread both at the beginning of the seam and at the end of the seam.

8. In a sewing machine, the combination with a bed fran'ie, of work-holding means carried thereby, a head movably mounted on the bed frame and carrying stitch-form m mechanism, means for giving said head its movement. means operated by the movement of said head to seize and hold the thread at the end of the seam, and means controlled by the head-moving means but operating independently of the movement of the head to cut the thread.

9. In a sewing machine, the combination with a bed frame, of Work-holding means carried thereby, a head movably mounted on the bed frame and carrying stitch-forming mechanism, means for giving said head its movement, means operated by the movement of said head to seize and hold the thread at the end of the seam, and means controlled by the head-moving means to cut the thread both at the end of the seam and at the beginning of the next seam.

10. In a sewing machine, the combination with a bed frame, of work-holding means carried thereby, a head movably mounted on the bed frame and carrying stitch-forming mechanism, a cam for giving said head its movement, a rock shaft extending vertically through the bed frame, a thread cutter carried by the work-holding means, means as sociated with the cam to oscillate the rock shaft, and an arm carried by the rock shaft above the bed frame and arranged to actuate the cutter.

11. In a sewing machine, the combination with a bed frame, of work-holding means carried thereby, a head movably mounted on the bed frame and carrying stitch-forming mechanism, a cam for moving said head, a thread cutter carried by the work-holding means, a rock shaft extending vertically through the bed frame and having an arm above the bed frame adapted to actuate the cutter and another arm beneath the bed frame, a lever for actuating the second arm and means rigid with the main ea In for controlling the lever.

12. In a sewing machine, the combination with work-holding means and stitelrtornr ing mechanism having a relative movement, of means operated by such relative movement to seize and hold the thread after the completion of the seam, a thread cutter movable relative. to said tln'ead-holding means and adapted to cut the thread between the threzul-holding means and the work, and cam-operated means operating independ ently of said relative movement to actuate said cutter.

13. In a sewing machine, the combination with work-holding means, stitch-forming mcchanisn'i and a main eam to give them a relative i'l'iovement, of means operated by such relative movement to seize and hold the thread at the end of the seam, a thread cutter arranged to out the thread between the thread-holding means and the work, and means rotating with the main cam to actuate said cutter.

14. In a sewing machine, the combination w th worleholding means and stitch-forming mechanism having a relative movement, of means operated by such relative movement to seize and hold the thread after the eompletion of the seam, and cam-operated means separate from the thread-holding means and operating independently of said relative movement to cut the thread between the thead-holding means and the Work.

In testimony whereof, I have signed my name to this specification.

JOHN KIEVVIGZ. 

